The purpose of this retrospective study was to assess the effect of the reduced medialisation of the Arrow reverse shoulder prosthesis on short-term clinical and radiological results. The clinical and radiological results of 47 Delta III reverse prostheses and 49 Arrow reverse prostheses were retrospectively compared at a minimum of twelve months follow-up. There was a significant increase (p < 1.10(-4)) in range of motion from the preoperative range in the two groups except for internal rotation in the Delta III group (p = 0.1). Radiological analysis on anteroposterior view in neutral position showed greater lateralisation (p < 0.001) with the Arrow prosthesis. Scapular notching was noted in 32 patients with a Delta III prosthesis, and in no instance with an Arrow prosthesis. Complication rates were 14.9% for the Delta group and 10.2% for the Arrow group. The design features of the Arrow prosthesis--reduced medialisation of the center of rotation with lateralisation of the humerus--were found to be associated with slight improvement in range of motion and absence of scapular notching.